Preanalyse

Preanalyse, or the pre-analytical phase, refers to all steps between test ordering and the start of the laboratory analysis. It includes patient preparation, specimen collection, labeling and documentation, specimen transport to the laboratory, and initial processing and storage before analysis. The aim is to preserve specimen integrity and ensure accurate test results.

Key elements of the preanalytical phase include patient preparation (such as appropriate fasting or timing, and consideration of medications that may affect results), specimen collection (choice of collection tube and volume, correct draw order, and avoidance of contamination), labeling and documentation (accurate patient identifiers and matching requisition with the specimen), and transport and handling (timely delivery and temperature control to prevent degradation). Pre-analytical processing covers receipt, initial handling, centrifugation or separation when required, and storage or aliquoting prior to analysis. Rejection criteria describe reasons to discard a specimen, such as insufficient volume, clotting, leakage, or improper container.

Significance: The pre-analytical phase is a major source of laboratory errors and variability, with potential impacts on patient safety and treatment decisions. Guidelines from bodies such as CLSI and ISO 15189 emphasize standardized procedures, traceability, and thorough documentation to minimize errors.

Common strategies for improvement include developing and enforcing standardized operating procedures, ongoing staff training, barcoding and automated pre-analytical systems, robust requisition practices, and reliable specimen transport networks. In German-speaking and some European contexts, the term preanalyse is used to denote this phase.